Process for manufacturing calcium sulfate-zinc sulfid pigment.



' chlorid by suitable reagents.

unman srAT s arana curios.

JOHN LATTIMORE CARPENTER, QFPALMERTON, PENNSYLVANIA.

I ROCESS FOR MANUFACTURING CALCIUM SULFATE-ZINC SULFID PIGMENT.

No Drawing.

To all'whom it may concern:

Be it known that I, JOHN LATTIMoRE CAR- PENTER, a citizen of the United States, and a resident of'Palmerton, in the county. of Carbon and State of Pennsylvania, have invented a new and Improved Process for 'Manufacturing Calcium Sulfate-Zinc Sulfid Pigment,,of which the following is a full,

clear, and exact description.

My invention relates to the manufacture of a compound spoken of as calcium sulfatez inc sulfid pigment, and has reference more particularly to' a processofobtaining the said compound from a solution of calcium chlorid by treating the samewith an'alkali sulfid and an appropriate zinc salt.

An object of the invention is to provide a simple and inexpensive process for the manufacture of calcium sulfate-zinc sulfid pigment by precipitating the same as a white substance from a solution of calcium Another object of the invention is to ob:

tain a product expressed substantially by the formula: GaSO,.ZnS, in which the ratio of calcium sulfate to zincsulfidin the expression stated can be varied Myprocess of manufacturmg calcium sulfate-zinc sulfid pigment is primarily 1ntended for the utilization of calcium chlorid obtained-as a by-product in certain industries, but it is self-evident that any solution of calcium chlorid in water can be used in my process. I; p y

The process conslsts in bringing together a solution of calcium chlorid, a solution of a soluble sulfid, or its products of hydrolysis, and a solution of zinc salt, thus forming a white precipitate.- This precipitate can then be treated in proper ways (which do not form part of my process) so it may be used as a pigment, rubber filler, etc.

While the ratio of CaSO to ZnS inthe final product is independent of the order of addition of the solutions specified, I prefer to use the following order: The soluble sulfid solution. I prefer to use is a solution of sodium sulfid which is run into the calcium Specification of Letters Patent.

chlorid solution, each at a rate dependent upon its concentration and at such a rate that the slight alkalinity in the calcium chlorid solution persists during the formation of the precipitate. The reaction can be expressed substantially as follows: CaCl +Na S+ZnSO =CaSO,.ZnSl-2NaCl.

chlorid, and, as seen from the reaction, the

liquid remaining after the precipitation car- ]Patented July 13, 1915. p Application filed July 1, 1913. Serial No. 776,786.

ries sodium chlorid in solution, hence a v quantity of the calcium salt would be dissolved. ,To lessen'the solution of CaSO,

during the formation of the white precipitate and during contact with the liquid, I use some easily soluble surfate, such as sodium sulfate or sulfuric acid, which is added to the calcium chlorid solution previous to its treatment with the soluble sulfid. A suflicient quantity of sulfuric acid is added to the calcium chlorid solution to make the same saturated with calcium sulfate, but not enough to cause noticeable pre- The solution of cal-- cium chlorid so saturated with calcium sulcipitation of the same.

fate is then treated with sodium sulfid and zinc sulfate, as stated.

' Ifit is desired to increase the proportion of calcium sulfate in -the white precipitate expressed substantially by the formula CaSO,.ZnS, a'soluble sulfate, preferably sulfuric acid is added to the calcium chlorid solution until the desired quantity of calcium sulfate precipitate is obtained, then solutions of sodium sulfid and zinc sulfate are added'in such ratios that the deposit formed during this addition is expressed substantially by the formula CaSo,.ZnS in addition to the calcium sulfate previously deposited.

If it is desired to increase the proportion of zinc sulfid in the white precipitate, it is accomplished by running into'the precipitating tank containing the white precipitate, expressed substantially by the formula CaSo,.ZnS, both a sulfid solution and a zinc solution until any calculated quantity of zinc sulfid is precipitated. Thus, by my process a white precipitate may be obtained carrying--. an v ratio. of calcium sulfate to zinc sulfidl; p

Having thus described myinvention, I claim a.- new and desire to secure by Letters Patent:

1. A process for manufacturing. 'alciunr sulfate-zinc sulfid pigment consisting in treating-a solution of calcium chlorid with a sulfid of an alkaline metal and a zinc salt treating a solution of calcium chlorid'with' sodium sulfid and zinc sulfate substantially as set forth. A processformanufaeturing calcium sulfate-zinc sulfid pigment consisting in forming a precipitate by treating a solution of calcium chlorid with an alkali sulfid until the solution is just alkaline, then adding simultaneously to the said'solution zinc'sulfate and an additional qu'antit} of alkali sulfid in such a ratio that the alkalinity in the chlorid solution will'persist during the, formation of the precipitate.

A process for manufacturing calcium sulfate zinc sulfid pigment consisting in treating a solution of calcium chlorid with.

sodium sulfid until the solution of calcium chlorid is just alkaline, then adding simultaneouslv' zine. sulfate and an additional quantity of sodium sulfid in such ratios that the alkalinity in the solution of calcium chlorid will persist during the precipitation. 6. A process for manufacturing calcium sulfate-Zinc snlfid pigment consisting in forming a precipitate by treating a solution of calcium chlorid with a compound containingthe radicle SO which will not react in the presence of a solublesulfid to form an insoluble sulfid. to cause the calcium chlorid solution to become saturated with calcium sulfate without noticeable precipitation of the same. then adding an alkali sulfid until the solution of calcium chlorid is just alkaline. then adding sinuiltaneousl to the said solutionzinc sulfate and an additional quantity of a'ikalisulfid each at a rate dependent upon its concentration and at such a rate that the slight alkalinit in the calcium chlorid solution persists during the formation of a precipitate from said solution. T. A process for i'miimfacturing calcium sulfate-Zinc sulfid pign'ient consisting in formin a precipitate by treating a solution of calcium chlorid with sulfuric acid to cause the calcium chlorid solution to become saturated with calcium sulfate without noticeable precipitation of the same, then adding a solution. of an alkali sulfid until the solution of 'a lcium"; chlorid is just alkaline.-

then adding simultanemisly to the said soluan additional quantity of tion ZlllC sulfate at. a rate dependent upon alkali sulfid each its concentration and atsuch a ate that? ing sodium sulfid until the solution of calcium chlorid 1s']ust alkaline, then addingsimultaneously to the said solution'zine sulfate and an additional quantity of sodium sulfid each at a rate dependent upon its concentration and at such a rate that a slight alkalinity in the calcium chlorid solution persists during the formation of the precipitate from said solution; a

9. ilproccss for manufacturing calcium sulfate-Zinc sullid pigment consisting in forming a precipitate by treating a solution of calcium chlorid with a compound containing the SQ radiclc which will not react in the presence of a soluble 'sulfid to form an insoluble sulfid. to cause the calcium chlorid solution to become saturated with calcium sulfate, but not. enough to cause noticeable precipitation, then adding to the solution of calcium chlorid an alkali sulfid until the said solution is just alkaline, then adding simultaneously to the solution of calcium chlorid zinc sulfate an additional quantity of alkali sulfid each at a rate dependent upon its-concentration and at such a rate that the slight alkalinity in the calcium chloridsolution persists until complete precipitation. then adding further alkali sulfid and Zinc sulfate until a predetermined quantity of zinc sultid is precipitated in addition to the precipitate previously formed.

10. A process formanufacturing calcium tsulfate zinc sulfid pigment consisting in forming a white precipitate by treating a solution of calcium chlorid with sulfuric acid and causing the calcium chlorid solution to become saturatedwith calcium sulfate but not enough to cause noticeable precipitation. then adding to the solution of calcium chlorid sodium sulfid until the calcium chlorid solution is just alkaline. then adding simultaneously to the solution of calcium chlorid the Zinc sulfate and an additional quantity of sodium sulfate each at a rate dependingupon its concentration and 1,140,000? I e a at such a ratethat the slight alkalinity in In testimony whereof have signed. my a the calcium chlorid solution persists until name to thisspecification in the presence of complete precipitation of a white substance, two SllbSCIlblHg witnesses.

then adding further sodium sulfid and zinc JOHN LATTIMOBE CARPENTER. 5 sulfate until a predetermined quantity of .Witnesses: 1

zine sulfid is precipitated in addition to the D. D. VAN MATER,

white precipitate previously formed. FELIX LAYAT. 

